Modern technology in ultrafast excitation/detection has opened the door to entirely new concepts in biological studies. Though the timescales of life processes themselves are slow, the physiocochemical forces that drive these processes are of molecular origin and can be extremely fast. Structure/function relationships may therefore be incomplete without this added dimension of time. Near term aims of this research program are: maintenance of state-of-the-art picosecond excitation/detection laboratory; study of the photophysicochemistry of isolated biological fluorescence probes, extrinsic and intrinsic; development of subnanosecond fluorescence techniques (polarized and unpolarized) for the study of in vitro and in vivo membranes and macromolecules containing these probes; use of these results to obtain new information about dynamical structure/function relationships; and search for new methods of differentiation between normal and abnormal/ diseased cells using the dimension of time, with possible applications to diagnostic medicine. Specific topics to be dealt with during the early phases of this research are isolated ANS/TNS probe molecules in neat and mixed polar solvents, ANS/TNS probes in inverse micelles and membranes, the dinoflagellate PCP photoreceptor, protein fluorescence studies, merocyanine 540, use of "crossed" 1054nm "beam" and higher harmonic "beams" to study effects of high transient fields, the Stentor coeruleus photophobic receptor, and the setting up of an argon-ion synchronously-pumped dye laser to complement present capabilities. Subnanosecond techniques for the study of the above problems will obviously allow better temporal resolution of the physical and system parameters, i.e. the disentanglement of fluorescence decays from heterogeneous sites in proteins and better resolution of complex polarization effects. A great advantage of subnanosecond spectroscopy is the possibility of studying so-called "nonfluorescent" probes. Chromophores that have fluorescence quantum yields as low as .0001 may still give large initial fluorescence signals on picosecond timescales.